Building with a positive ecological footprint: Development and evaluation of a Cradle to Cradle ®-inspired energy-plus house

Energy-plus houses have been taking on particular significance in future-oriented residential construction. Therefore, it should be possible to build CO2-neutral buildings that can meet their own energy demand and in fact supply energy for additional consumers, e.g. electromobility. Based on the example of Cradle to Cradle® (C2C), the aim is moreover to demonstrate how buildings can already be constructed with an essentially positive ecological footprint today. This research project analyzed and described how the fundamental C2C principles: “Waste equals food,” “Use current solar income” and “Celebrate Diversity” can be transferred to and implemented in the “nexushaus,” designed and built for the Solar Decathlon competition 2015. Material. Technical and biological nutrient cycles of the “nexushaus” were defined and described in the list of materials along with the specified environmental indicators. A healthy residential environment achieved by pollutant-free materials is discussed. This is followed by a detailed discussion of the recyclability of the nexushaus. Water. The water footprint of the building structure is analyzed. Potential measures to enable eco-sufficient use of water as a resource are described. Gray-water recycling saves drinking water and can be used for the irrigation of green spaces. The use of accumulating condensation water supports self-sufficient food production (e.g. aquaponics). If rainwater is harvested, its use for drinking water or garden irrigation should also be considered. Diversity. The architectural design of the house offers cultural benefits: barrier-free access and diverse qualities of stay in the indoor and outdoor space by outlooks and partial insights that accommodate places of retreat. Additional habitats for animals and plants can be provided in the form of green roofs and façades